PROJECT SUMMARY This study will leverage nationally-representative survey data to determine the current prevalence, severity, geographic distribution, and determinants of food allergy among the US population. In 2016, we collaborated with an expert panel of primary care physicians, allergists, epidemiologists, biostatisticians and health services researchers to develop and administer comprehensive population-based cross-sectional surveys assessing the current prevalence of food allergy among 80,000 U.S. households. The surveys were administered by the independent research organization NORC at the University of Chicago, and population-weighted results are now available for analysis. This study will analyze and interpret these nationally-representative survey data in order to determine the prevalence, distribution, and determinants of food allergy and the development of tolerance to previously allergenic foods among adults and children in the US, and to assess recent trends in childhood food allergy prevalence since our prior 2009-2010 pediatric prevalence survey. These data will be the first to characterize food allergy among adults, including adult-onset food allergy, and the development of tolerance. These data will also provide a much-needed update to our landmark 2009-2010 study of childhood food allergy, the estimates from which remain the most widely cited estimates of childhood food allergy prevalence in the US. Furthermore these data will permit a comprehensive look into current FA diagnosis and management trends, and will determine the degree to which current clinical and self-management practices are consistent with those recommended by the 2010 NIAID-sponsored Guidelines for the Diagnosis and Management of Food Allergy. Findings from the present study will increase our understanding of the interplay of socio-environmental and individual factors on the development of new-onset food allergy and the development of tolerance among adults and children. By characterizing current FA, we will inform the context of future food allergy research regarding diagnosis, management, and treatment of this rapidly emerging, multi-generational health concern.